Since the earliest examination of cellular structures, biologists have been fascinated by observing cells using light microscopy. The advent of fluorescent labeling technologies plus the plethora of sophisticated light microscope techniques now available make studying dynamic processes in living cells almost commonplace. The ability to visualize, track, and quantify molecules and events in living cells with high spatial and temporal resolution is essential for understanding biological systems. The precise understanding of the molecular mechanisms of neurodegenerative processes could lead to new biological targets for developing leading new drugs that can be effectively used for the ultimate cure of these diseases. In neurological sciences, for example, understanding the translocation of proteins, or protein complexes, from one subcellular location to another is an important aspect for effectively developing novel drugs for various neurodegenerative diseases. Live-cell fluorescence imaging (in particular, high content analysis), however, is seriously limited by the availability of photostable fluorescent probes. The existing fluorescent probes are not appropriate for long- term live-cell imaging and tracing due to their poor photostability. Additionally, these probes are quite toxic to cells if used at high concentrations. Recently, quantum dots (Qdots) that are made from fluorescent semiconductor materials have been proposed for live-cell imaging due to their extremely high photostability. However, their huge size seriously affects the activities of the biological target molecules that are tagged. Uniformity and reproducibility of Qdot labeling have been very challenging. Some of these fluorescent probes require excitation near UV wavelength that cause cell damage and early apoptosis and prevent these probes from being useful for long-term live-cell imaging. ABD Bioquest will collaborate with the Southern Research Institute to develop novel perylene-based fluorescent probes, which have the following properties, for live cell imaging. 1) Small molecular weight. 2) Minimal toxic to cells. 3) High intensity emission with narrow bandwidth. 4) High photostability. 5) Visible wavelength (prefer near to red) excitation. 6) Easy conjugation with antibodies. Two specific aims will be addressed in this Phase I application. Specific Aim 1: Design, synthesize and characterize novel perylene-based fluorescent dyes Specific Aim 2: Evaluate the perylene dye's feasibility for live cell immunofluorescence imaging. The successful completion of these aims will produce a powerful fluorescent probe that can be used for exploring novel applications of high content analysis and screening in live cells. [unreadable] [unreadable] [unreadable]